1. Field of the Invention
The present invention relates to a cassette having a radiation conversion panel for detecting a radiation that has passed through a subject and converting the detected radiation into radiation image information, and a mobile X-ray image capturing apparatus which uses such a cassette.
2. Description of the Related Art
In the medical field, there have widely been used radiation image capturing apparatus which apply a radiation to a subject and guide the radiation that has passed through the subject to a radiation conversion panel, which capture a radiation image from the radiation. Known forms of the radiation conversion panel include a conventional radiation film for recording a radiation image by way of exposure, and a stimulable phosphor panel for storing a radiation energy representing a radiation image in a phosphor and reproducing the radiation image as stimulated light by applying stimulating light to the phosphor. The radiation film with the recorded radiation image is supplied to a developing device to develop the radiation image, or the stimulable phosphor panel is supplied to a reading device to read and obtain the radiation image as a visible image.
In the operating room or the like, it is necessary to read out a recorded radiation image immediately from a radiation conversion panel after the radiation image is captured for the purpose of quickly and appropriately treating the patient. As a radiation conversion panel which meets such a requirement, there has been developed a radiation detector having a solid-state detector for converting a radiation directly into an electric signal or converting a radiation into visible light with a scintillator and then converting the visible light into an electric signal to read a detected radiation image.
In recent years, there have been growing demands for capturing an image of a critically ill patient who cannot easily be moved out of his or her room and also for capturing an image in emergency in an operating room. As a result, there have been increasing needs for apparatus which allow surgeons or doctors to confirm, quickly with high image quality, images that have been captured in clinical and surgical environments other than X-ray image capturing rooms.
To meet such needs, mobile X-ray image capturing apparatus have been proposed as disclosed in Japanese Laid-Open Patent Publication No. 2004-141473 and Japanese Laid-Open Patent Publication No. 2005-013310.
According to the mobile X-ray image capturing apparatus disclosed in Japanese Laid-Open Patent Publication No. 2004-141473, the radiation image of a patient is captured and the radiation image information is recorded in a cassette having a radiation detector, and the recorded radiation image information is transferred from the cassette via an external interface to a storage medium or a display unit by way of wireless communications immediately after the radiation image information is captured. Alternatively, the cassette with the radiation image information recorded therein is carried to a room where images can be displayed, and only the cassette is connected to a display unit or a storage medium in the room and the radiation image information is transferred from the cassette to the display unit or the storage medium.
According to the mobile X-ray image capturing apparatus disclosed in Japanese Laid-Open Patent Publication No. 2005-013310, the radiation image information of a patient is captured and recorded in a cassette, and the cassette is carried to a position within the communication range of a cassette box, whereupon the cassette automatically starts transferring the radiation image information to the cassette box.
The mobile X-ray image capturing apparatus may be required to store the radiation image information of a plurality of patients or a plurality of pieces of radiation image information of a single patient in an image memory in the cassette.
Since the radiation image information has a large volume of data, the image memory in the cassette needs to be of a large storage capacity for storing the radiation image information of plural patients or the plural pieces of radiation image information of a single patient.
There has been a demand for the quick transmission of radiation image information that has been recorded in the cassette in an image capturing site by the mobile X-ray image capturing apparatus, to a radiation image information archival facility such as a server or the like without delay.